Likely just a path or permissions issue, check...
/fckeditor/editor/filemanager/connectors/php/config.php
Code:
$Config['UserFilesPath'] = '/userfiles/' ;
Try changing it to a different directory.
Eg. if your store resides in /store, try...
Code:
$Config['UserFilesPath'] = '/store/userfiles/' ;
Ensure the userfiles directory is writable (CHMOD 777)